and bill weir in new york city, this is a special edition of "nightline," no way out. september 20th, 2012. >> good evening, i'm bill weir. well, tonight, across this country, some 80,000 prisoners are locked in solitary confinement. prison reformers pushed it as a humane alternative to hanging, almost 200 years ago. but some modern reformers think it is pure torture. practice has led to congressional hearings, u.n. reports, inmate hunger strikes. to better understand the toll of forced solitude, abc's dan harris volunteered to spend 48 hours in the hole. >> reporter: i'm cuffed and stuffed in the back of a sheriff's vehicle. >> right in front of you. turn around, put your hands -- >> reporter: this is everybody's worst nightmare. >> come on this way, please. >> reporter: the fther we get into this, the more real it feels. >> look up at the camera, please. >> everything you need for your spell upstairs. shoes, a blanket. >> reporter: i am about to enter what some have called a monster factory. we arrive at what will be my new home. it's 7 by 12 feet, all concrete and m